Filter out some duplicate author names in update_authors.sh

bin/update_authors.sh

@@ -1,6 +1,6 @@
 # Combine existing list of authors with everyone known in git, sort, add header.
 tail --lines=+3 AUTHORS > AUTHORS.tmp
-git log --format='%aN' | grep -v abraidwood >> AUTHORS.tmp
+git log --format='%aN' | grep -v abraidwood | grep -v Rich-Harris | grep -v ForbesLindesay >> AUTHORS.tmp
 echo -e "List of Acorn contributors. Updated before every release.\n" > AUTHORS
 sort -u AUTHORS.tmp >> AUTHORS
 rm -f AUTHORS.tmp